Priming device for internal combustion engines



Sept 14, 1937. M. c. P. THIEULIN ET AL 2,093,218

PRIMING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Dec. 27, 1934 W////////,,,A 117111 lgnga m/ ill Patented Sept. 14, 1937 PRIMING DEVICE FOR INTERNAL COMBUSTION ENGINES Maurice Clment Philippe Thieulin and Paul Xavier Auguste Gistucci, Paris, France, assignors to Societe Generaie des Carburateurs Zenith, Levallois-Perret, France Application December 27, 1934, Serial No. 759,402 In Belgium January 4, 1934 10 Claims.

The present invention relates to fuel feed devices for internal combustion engines of the type including a main carburetter provided with a mixing tube, which will be hereinafter called main mixing tube, and an auxiliary starting carburetter provided with a fuel mixture outlet opening into said main mixing tube and controlled by means of a valve.

Devices of this kind serve to facilitate the starting of the engine from cold by supplying a rich mixture which is added to the normal mixture fed by the mam carburetter as long as the engine is not warm enough for working in a satisfactory manner with the mixture fed by the main carburetter alone. In these devices, the valve controlling the auxiliary carburetter fuel mixture outlet serves to bring said auxiliary carburetter out of action when the engine is warm.

In devices of this kind, a thermostatic element subjected to the same-variations of temperature as the engine controls said valve so as to close it when the engine is sufficiently warm'. With such an arrangement, the percentage of fuel in the mixture fed to the engine by the auxiliary carburetter remains unchanged for the whole of the time for which said auxiliary carburetter is in operation. In other words, while means are provided for gradually reducing the amount of mixture fed by the auxiliary carburetter as the engine is growing warmer, the proportions of air and fuel in said mixture remain uniform. Therefore, when the engine is already getting warm and the above mentioned valve of the auxiliary carburetter is but partly closed, the mixture fed to the engine by the auxiliary carburetter is too rich and a defective working of the engine is the consequence.

, This drawback is especially serious when the auxiliary starting carburetter is so devised as to supply a fuel mixture in which the percentage of fuel decreases as the rate of feed of said carburetter increases. The purpose of this arrangement is to supply a richer mixture whenthe engine is just starting and its speed of revolution is low than when the engine has already gathered speed. But as the engine gathers speed it also grows warmer so that, despite the increased suction resulting from the acceleration of the' engine, the gradual closing of the control valve of the auxiliary carburetter under the action of the thermostatic element causes the rate of feed of the auxiliary carburetter to decrease gradually, whereby the mixture fed by said carburetter becomes richer when it should, on the contrary, become weaker.

The object of the present invention is to provide a fuel feed device which obviates this drawback, that is to say a device with which the percentage of fuel in the fuel mixture fed by the auxiliary starting carburetter decreases as the 5 rate of feed of this auxiliary carburetter to the engine decreases in response to a rise of temperature.

According to the present invention, the auxiliary carburetter is provided with both a fuel mixture valve for controlling the rate of.feed from said auxiliary carburetter to the engine, and an air inlet valve for controlling the inflow of air to said auxiliary carburetter, and thermostatic means subjected to the action of the variations of temperature of the engine are adapted to act on the first mentioned valve in the direction of closing thereof and on the second mentioned valve in the direction of opening thereof when said temperature rises. The suctionin the mixing chamber of the auxiliary carburetter and therefore the rate of feed of fuel to said chamber decrease when the air inlet valve opens wider, so that the percentage of fuel in the fuel mixture fed by the auxiliary carburetter decreases. Therefore, when the temperature rises, the thermostatic device causes both .the rate of feed of the fuel mixture from the auxiliary carburetter to the engine and the percentage of fuel in said fuel mixture to decrease.

When the thermostatic device is so arranged as to be influenced by both the temperature of the engine and the temperature of the surrounding medium, the device according to the present invention modifies the composition of the fuel mixture supplied by the auxiliary carburetter in accordance with both the temperature of the engine and the temperature of the surrounding medium.

The thermostatic device may be of any kind whatever (expansible container filled with a liquid, a gas, or a volatile liquid, bi-metallic strip, etc.). It may be disposed either close to the exhaust pipe of the engine, or under the hood of the engine, or again in, the water circulation system thereof. In any of these cases the thermostatic device is, subjected to the action of both the temperature of the engine and the temperature of the surrounding medium, since the temperature of the exhaust pipe, the temperature inside the hood, and the temperature of the cooling water of the circulation system obviously depend on both the temperature of the engine and the temperature of the surrounding medium.

According to a preferred embodiment of the present invention, the inflow of air to the aux- 65 casing 44 is determined by a stop 43 carried by a iliary starting carburetter is controlled by means of a spring-loaded valve operative bythe suction in the mixing chamber of said auxiliary carburetter and the thermostatic device controls the position of a movable stop limiting the displacements of said valve in the direction of closing thereof. The minimum amount of opening of said valve imposed by said stop therefore increases when the temperature increases. Eventually, this thermostatic device also controls a second movable stop limiting the displacements of said valve in the direction of opening thereof. Owing to this second mentioned stop, the maximum degree of opening of said valve is increased when the temperature rises.

The air inlet control valve operated by the thermostatic device may act on the whole of the air entering the auxiliary starting carburetter or on the main air flow. But, according to another feature of the present invention, said control valve may also act on an air inlet conduit opening into the fuel feed pipe leading to the main mixing chamber of the auxiliary carburetter. With this arrangement, the opening of this control valve reduces the suction in said fuel feed pipe and therefore weakens the fuel mixture when the temperature rises.

It has been suggested to make use, in auxiliary starting carburetters, of a submerged jet for supplying fuel to the fuel feed conduit. Owing to the known properties of submerged jets, the mixture produced by such a device becomes weaker when the rate of feed of the auxiliary carburetter increases, together with the speed-of revolution of the engine, which is favorable for starting from cold. The present invention can be applied to devices of this kind by causing a valve operated through thermostatic means to control the passage through which emulsifying air is fed to the submerged jet. When the section of flow through said passage increases as a result of a rise of the temperature, the rate of fuel flow through the submerged jet decreases.

These and otherfeatures of the present invention will clearly result from the following detailed description of some specific embodiments thereof.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawing, given merely by way of example, and in which:

Fig. 1 is a longitudinal sectional view showing, an auxiliary starting carburetter provided with a suction actuated valve for controlling the air inlet;

Fig. 2 is a longitudinal sectional view of a modification of this auxiliary carburetter;

Fig. 3 is a longitudinal sectional view of an auxiliary starting carburetter in which the main air inlet is controlled by a suction actuated valve, while the emulsifying air inlet is controlled through thermostatic means.

In the embodiment shown in Fig. 1, theauxiliary starting carburetter comprises a mixing chamber 39 connected with the mixing pipe of the A spring 41, stronger than", is interposed be-' tween the other end of box 43 and the corresponding end of casing 44. The position of box 43 in This apparatus may be fitted directly on the intake manifold of the engine, as shown. In this case, thermostatic box 43 is subjected to the action of a temperature of the air present in the hood of the engine, and holes 45, provided in the wall of casing 44, permit air blown by the fan to circulate around box 43, so as to facilitate the heating of this box. The apparatus may also be fixed at another place, for instance in the vicinity of the exhaust pipe. In the latter case the fuel mixture outlet 40 is connected to the intake manifold through any suitable conduit.

A fuel outlet 56 opening into mixing chamber 33 is connected to the float chamber 5 of the main carburetter 2 through a fuel conduit 55. Air is fed to said chamber 33 through an air inlet 50 communicating with the atmosphere thnough ports 5| provided in casing 44. This air inlet 53 is controlled by a valve 52 slidable along the stem 42 of outlet valve 4|. This valve 52 is subjected to the action of a spring 53 interposed between valve 52 and valve 4i. Stem 42 is provided with a shoulder 54 adapted to prevent valve 52 from being applied onto its seat by spring 53 when thermostatic box 43 is expanded.

This device works in the following manner:

Fig. 1 shows the position of the parts when the engine is not running, said engine being cold and the atmospheric temperature being supposed to be low. Box 43 is sufllciently shrunk for placing shoulder 54 in a position such that air valve 52 can rest upon its seat under the effect of the thrust of spring 53. In this position of stem 42 valve 4i is at a sufficient distance from its seat for fully opening mixture outlet 40. When the engine is started, it creates a suction which is transmitted through outlet 40 and chamber 33 to air valve 52 and moves said valve away from its seat as soon as this suction is capable of overcoming the resistance of spring 53. The suction -in chamber 33 draws in fuel through fuel inlet 56. As the speed of revolution of the engine increases, valve 52 opens more and more and spring 53 is more and more compressed. This gradual opening of valve 52 prevents the suction in chamber 39 from increasing as rapidly as the air feed. Therefore the rate of feed of the fuel sucked in through fuel inlet 55, which depends on the suction in chamber 33, increases less rapidly than the air feed, so that the mixture fed by the auxiliary carburetter becomes weaker as the speed of revolution of the engine increases.

As the engine grows warmer, the temperature under the hood of the engine, where box 43 is located, rises. Box 43 expands and causes valve 4i to move toward its closed position. This closing displacement of valve 4i gradually reduces the rate of feed of the fuel mixture to the engine.

As air valve 52 is urged toward its closed position by spring 53, if said valve were left free to move, the section of flow past said air inlet valve 52 would decrease as the section of flow past mixture outlet valve 4i decreases, so that the suction in chamber 33 would decrease much less rapidly than the rate of feed of air past valve 52. Therefore, since the rate of feed of fuel through fuel outlet 53 varies in accordance with the suction in chamber 33, this rate of feed of fuel would decrease less rapidly than the rate of feed of air past valve 52, which would correspond to th mixture fed to the engine becoming richer when it must, on the contrary, become weaker.

But the shoulder 54 carried by the stem 42 of valve 4| is adapted to cooperate with valve 52 so as to prevent it from closing when valve 4| has been moved a certain distance toward its closed position by the expansion of thermostatic box 43. In other words, from a certain temperature up, box 43 imposes, through shoulder54, a

minimum amount of opening of valve 52, which minimum amount increases as the temperature rises.

This minimum opening of valve 52 imposed by the position of stop 54 reduces the suction in chamber 39 which acts on fuel outlet 56, thus suitably reducing the feed of fuel through said fuel outlet.

As the temperature further increases, the expansion of box 43 finally brings valve 4| onto its seat, so as to fully close the mixture outlet 40 and, from this time on, further expansion of box 43 compresses spring 41 and moves nut 48 away from the outer end face of casing 44.

When the engine is cold and not running, if the atmospheric temperature is relatively high box 43 may be suiliciently expanded for bringing shoulder 54 in a position such that valve 52 is partly open. Under these conditions, the mixture fed by the auxiliary carburetter when the latter is brought into action is weaker than for low atmospheric temperatures, which correspond to said valve 52 being applied against its seat.

In the device shown in Fig. 1, the valve 52 is caused to open more and more against the pressure of spring 53 as the suction increases due to an increase in the engine speed, and the mixture supplied grows accordingly weaker and weaker. It was found that in certain engines this weakening action was objectionable from a predetermined speed up, the mixture becoming too weak beyond said speed.

In the apparatus shown by Fig. 2, the opening displacement of air valve 52 under the action of the suction in chamber 39 is limited by a stop 51 carried by the stem 42 of mixture valve '4l, whereby the mixture is prevented to become too weak as the engine speed increases. It is pointed out, however, that the suitable mixture to be supplied to the engine at high speeds should be weaker as the temperature rises. Shoulder 51, which moves together with valve 4| and the stem 42 thereof, under the action of thermostatic box 43, increases the maximum permissible opening of valve 52 when the temperature rises, whereby themixture supplied at high engine speeds, for which the suction maintains valve 52 against shoulder 51, becomes weaker as the temperature rises.

The device shown in Fig. 3 includes a mixing chamber 11 connected with the intake manifold of the engine through a mixture outlet 18 controlled by means of a valve 19. Valve 19 is carried by a rod including a cylindrical portion 80 and another cylindrical portion 81 of smaller diameter which is connected with one end 01' thermostatic box 8|. The cylindrical portion 88 of the valve stem is slidable in the cylindrical bore of a piece 88 provided, on its outer surface, withan. annular groove 89. This groove 88 is connected with the cylindrical bore of piece 88 through -radial holes 90 which are normally closed by cylindrical portion 80 of the valve stem.

Mixing chamber 11 is provided'with an air intake 82 controlled by a valve 83 operated by the suction in chamber 11, against the action of a spring 84. Mixing chamber 11 is fed with fuel through an outlet 85 supplying air emulsified with fuel, said outlet being connected with the float chamber. of the main carburetter (not shown) through a passage 86, annular groove 88, and a conduit 9| communicating with the float chamber.

When the temperature rises, thermostatic box 8| moves outlet valve 19in the closing direction thereof through stem 81-80 and holes 98 are successively uncovered by cylindrical portion 80. These holes then connect groove 89 with the atmosphere through chamber 92 and ports 85 provided in the wall of said chamber. Emulsifying air is thus introduced into fuel conduit 86, and reduces the rate of feed of fuel through outlet 85. Independently of the temperature, spring loaded valve 83, which controls the main air intake 82, weakens the mixture supplied by the auxiliary carburetter when said air valve is lifted from its seat, thus admitting a greater amount of air, when the speed of revolution of the engine increases.

While we have, in the above description, en-' deavoured to disclose what we deem to be practical and efllcient embodiments of the present invention, it should be well understood that we do not wish to be limited thereto as theremight be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

.What we claim is:

1. An auxiliary carburetter for use in conjunction with a main carburetter, which comprises, in combination, an air inlet, a suction actuated loaded valve for controlling said air inlet, thermostatically controlled means for simultaneously reducing the rate of feed of fuel mixture delivered by said auxiliary carburetter and increasing the rate of feed of air entering said auxiliary carburetter. as the temperature rises.

2. An auxiliary carburetter for use in conjunction with -a main carburetter, which comprises, in combination, an air inlet, a suction actuated loaded valve for controlling said air inlet, thermostatically controlled means for simultaneously reducing the rate of feed of fuel mixture delivered by said auxiliary carburetter and the richness of said mixture as the temperature rises.

3. An auxiliary carburetter for use in conjunction with a main carburetter, which comprises, in combination, a mixing chamber having a mixtureoutlet and an air inlet, a valve arranged to control the flow of fuel mixture through said,

outlet, a spring loaded valve operative by the suction in said chamber for controlling the flow of air through said inlet, movable .stopping means for limiting the closing displacements of said spring loaded valve, and thermostatically controlled means for simultaneously closing the first mentioned valve and moving said stopping means in the direction that increases the minimum degree of opening of said second mentioned valve when the temperature of said thermostatic means rises.

4. An auxiliary carburetter for use in conjunction with a main carburetter, which comprises, in combination, a mixing chamber having a mixture outlet and an air inlet, a valve arranged to air through said inlet, movable stopping means for limiting the closing displacements of said spring loaded valve, movable stopping means for limiting the opening displacements of said spring loaded valve, and thermostatically controlled means for simultaneously closing the first mentioned valve and moving both of said stopping means in the direction that increases the minimum and the maximum degree of opening of said second mentioned val've when the temperature of said thermostatic means rises.

5. An auxiliary carburetter for use in coniunction with a main carburetter, which comprises, in combination, a mixing chamber having a mixture outlet and an air inlet, a fuel feed conduit opening into said chamber, a rod extending through said air inlet, a valve adapted to control the flow of fuel mixture through said mixture outlet operatively connected with said rod, a valve slidable on said rod adapted to cooperate with said air inlet for controlling the inflow of air therethrough, means for yieldingly opposing the opening displacements of said slidable valve under the effect of the suction in said chamber, a stop carried by said rod on the outer side of said slidable valve so as to limit the closing displacements thereof, and a thermostatic expansible box having one of its ends connected to said rod so as to force it in said chamber and gradually close said mixture outlet when the temperature rises.

6. An auxiliary carburetter according to claim 5, further com rising a second stop on the opposite side of sa d slidable valve so as to limit the opening displacements thereof.

7. An auxiliary carburetter for use in conjunction with a main carburetter, which comprises, in combination, a mixing chamber having a mixture outlet and a main air intake, a suction actuated loaded valve in said main air intake, valve means forcontrolling the flow of fuel mixture through said outlet, a fuel feed conduit opening into said chamber, an air intake for introducing emulsifying air into said conduit, valve means for controlling the inflow of air through said second mentioned air intake, and thermostatically controlled means for simultaneously closing the first mentioned valve means and opening the second mentioned valve means when the temperature rises.

8. An auxiliary carburetter according to claim '7, further including a submerged jet arranged to control the flow of fuel to said fuel feed conduit.

9. An auxiliary carburetter for use in condunction with a. main carburetter, which comprises, in combination, a. mixing chamber having a mlxture outlet and a main air intake, a spring loaded valve for, controlling the inflow. of air through said intake, valve means for controlling the flow of fuel mixture through said outlet, 9, fuel feed conduit opening into said chamber, an auxiliary air intake to said mixing chamber, valve means for controlling the inflow of air through said auxiliary air intake, and thermostatically controlled means for simultaneously closing the first mentioned valve means and opening the second mentioned valve means when the temperature 10. An auxiliary carburetter for use in conjunction with a main carburetter, which comprises, in combination, a mixture outlet and an air inlet, a spring loaded valve operative by the suction in said chamber for controlling the inflow of air through said inlet, a fuel feed passage opening into said chamber, a valve for controlling the flow of fuel mixture through said outlet, a rod for said valve, means operative by said rod for introducing air into said fuel feed passage, and thermostatically controlled means for causing said rod to simultaneously close the second mentioned valve and bring said means for introducing air into said fuel feed passage into action, when the temperature rises.

MAURICE CLEMENT PHILIPPE THIEULIN. PAUL XAVIER AUGUSTE GISTUCCI. 

